The L5 is aimed at the professional home builder, room addition contractor, or tenant improvement contractor who wants a self leveling laser. Compensated self leveling means that once the unit is rough leveled, it will automatically adjust for slight vibrations, wind, and temperature expansion or contraction of the tripod. If the unit is disturbed so that it is out of its self leveling range, it will stop functioning until it is releveled. It features a highly visible (635nm) red rotating beam, along with a plumb spot. The plumb spot can be used to transfer points from floor to ceiling, and will provide a 90 degree reference when the laser is in its vertical mode. This product is designed to take you from grading to form setting through interior finish work.